Scroll arrow in the menu bar does not work

[Wiwaltill]

The scroll arrow in the menu bar (see image) does not work. If a pageflow has many chapters and the arrow is visible, however, the menu bar does not jump to the next chapters when clicked.

Example

In the example, 19 chapters are used. Unfortunately, nothing happens when the arrow is clicked.

[tf]

I can reproduce problems on Mobile Safari on iPad. Where do you see these issues?

[Wiwaltill]

MacOS Safari v.15.5

EDIT: In other browsers, the arrow works.